Despite numerous statistical analyses to assess the pattern of dental caries in primary dentition, there are still some fundamental questions that remain unanswered. As an example, it is well believed among dentist that there are spatial symmetries in the mouth with respect to caries, but this has never been shown in a statistical sense. A unique database that provides detailed tooth-level data with respect to dental caries, which could help answer some of these questions, is the Signal Tandmobiel project in Flanders (Belgium). This proposal is for a very extensive study that comprises both cross-sectional and longitudinal investigations of oral hygiene among Flemish schoolchildren. Its objectives are to assess determinants of oral hygiene among children born in 1989 and to assess the effect of yearly oral hygiene education conducted at randomly selected schools. A tooth-surface level analysis of this data poses a number of difficulties due to inherent spatial association of surfaces in the mouth and repeated measurements generated from the same surface over time. The objective of this proposal is to develop a statistical methodology for secondary analysis of dental caries data generated from this extensive epidemiologic study. Specifically, we propose (1) to develop statistical models for spatial-temporal binary data and develop models for multivariate time-to-event data with applications to dental caries in primary teeth, which will be used to answer questions related to tooth surface susceptibility to caries experience, symmetries in the mouth with respect to dental caries, and differences in surface susceptibility according to caries risk groups; (2) to monitor the quality of the proposed statistical models; and (3) to investigate the influence of the missing data mechanism on the proposed regression models. A key goal of this statistical study is to improve our ability to design, analyze, and interpret complex dependent data generated from clinical trials and epidemiologic studies in dental research. [unreadable] [unreadable]